1. Technical Field
The present invention relates to data flow management and, more particularly, to management of video streams over cellular networks.
2. Description of the Related Art
Recent years have witnessed a significant increase in data traffic on cellular networks, especially in the form of videos. The increase of video traffic in proportion to network use, coupled with the scarcity of the frequency spectrum, often leads to congestion at the wireless links. For non-elastic traffic such as voice and streaming video, where on-time reception of data is important for maintaining a high quality of experience, admission control may be used for flow management.
Unlike voice traffic, however, admission control is much harder with video streaming due to several challenges. Firstly, most videos involve variable bitrate coding; leading to significantly different video frame sizes with time. Hence, pre-provisioning certain amount of resources for each video flow is either too conservative, leading to under-utilization of wireless resources, or too aggressive, leading to bad video quality for all users. Secondly, to add to the complexity of provisioning, channel capacity can fluctuate significantly with time. Specifically, after a certain number of flows have been admitted, the capacity might decrease due to interference, mobility, etc. Such capacity mismatch may adversely affect many or even all flows, depending on the scheduling policy used across the admitted flows.
One solution builds on the wireless resource virtualization paradigm. This solution admits a greater number of flows relative to the basestation capacity to ensure maximum basestation utilization in the presence of video and capacity fluctuations. However, there are still network conditions that cannot be handled, or could be handled more gracefully, than the existing solutions allow.